To better understand cell function in health and disease, we need to visualize the localization of protein complexes and dynamic changes in different cellular compartments in response to normal stimuli or insult. To this end, we will develop "Nanomicroscopes" for fluorescence imaging to measure structures and their dynamics inside a cell with a 3D spatial resolution down to the scale of 20-40 nm while maintaining the microscopic whole cell scale over a 20-100 um range. In a multi-disciplinary engineering and biological sciences effort, we will develop and apply such "Nanomicroscopes" to cardiovascular research, specifically to a pressure-overload model of heart failure. The overall hypothesis states that, stress-induced structural rearrangements -in the subcellular location and interactions- of key signaling protein complexes in the heart and blood vessels differentially contribute to the onset and progression of heart failure. We show exciting preliminary advances in the design of a novel Reflexion Nanomicroscope that achieves a full-width-half- maximum (FWHM) of ~100 nm lateral resolution. The Specific Aims are: Aim 1. TO DEVELOP NOVEL NANOMICROSCOPIES TO MEASURE STATIC AND DYNAMIC PROTEIN-PROTEIN INTERACTIONS. 1.1. To further improve the novel Reflexion Confocal Nanomicroscope by constructing a fast acquisition multicolor Reflexion Confocal with FRET for living cells and develop the theory to enhance its resolution beyond. 1.2. To combine STED with 4Pi microscopy to achieve 10-20 nm 3D resolution and expand to two fluorescene wavelengths for protein colocalization imaging. Aim 2. TO APPLY THE NOVEL NANOMICROSCOPES TO VISUALIZE STATIC AND DYNAMIC CHANGES OF MACROMOLECULAR COMPLEXES REGULATING HEART AND VASCULAR SIGNALING IN A PRESSURE OVERLOAD MODEL OF HEART FAILURE BY DETERMINING: 2.1. The structural basis of local stress signaling (p38 kinase signalsome) and EC-coupling defects in cardiomyocytes under stress and heart failure. 2.2. The spatiotemporal remodeling of proteasome subunits and their assembly in normal, stressed and protected (e.g. estrogen signals) myocardium. 2.3. The stress-induced dynamics/remodeling of aortic GPCR-Src tyrosine kinase signaling complexes that exacerbate heart failure. Nano-imaging will be complemented by state-of-the-art molecular manipulations, biochemical and proteomic approaches. These studies will be the basis to unravel -at the nanoscale level- the structural map of protein complexes at the subcellular level, their localization and dynamic interactions in cardiovascular disease. Identifying the structural basis of cell signaling pathways/networks will provide opportunities to discover new therapeutic targets to alleviate cardiovascular disease, a leading cause of death in the United States.